Heat resistant chocolate products are of particular interest for hot countries, where conventional chocolate products become soft and sticky at temperatures of 30° C. or higher. Therefore, it is desirable to provide a heat-resistant chocolate product, which can withstand temperatures of 30° C. or more without becoming soft and sticky.
Heat resistant chocolate may be applied for solid tablets or bars as well as compounded or enrobed products such as chocolate coated wafers, biscuits or the like.
Many published (patent) documents are known which disclose methods of producing heat resistant chocolate products. The majority of these patents, however, describe the production of solid tablets or bars, while compounded or enrobed products cannot be produced by the disclosed technologies.
Examples are U.S. Pat. No. 6,488,979 and U.S. Pat. No. 4,980,192 (and many others). In U.S. Pat. No. 6,488,979 and U.S. Pat. No. 4,980,192 a method for preparing heat resistant chocolate is described, wherein a polyol, such as glycerine or sorbitol, is admixed to conventional chocolate. The major drawback of this method is the short working time remaining upon mixing before the mixture is firming up. The same problem occurs when mixing conventional chocolate mass with a water-containing phase. This may be overcome by different means to encapsulate water (e.g. by emulsions or saturated polyol solutions) and/or to reduce the mixing time (e.g. static mixers).
In U.S. Pat. No. 5,149,560, U.S. Pat. No. 5,160,760, U.S. Pat. No. 5,486,376 and U.S. Pat. No. 6,165,540 similar methods based on the use of a water-in-oil emulsion for preparing heat-resistant chocolate are described. Mixing the polyol encapsulated in an emulsion with chocolate gives a limited extension of working time which is suitable for a more convenient production of solid chocolate products, but not for the production of compounded or enrobed products with interiors or inclusions or which are filled.
Another example for using emulsions as encapsulation media is disclosed in EP 0 033 718. Therein a chocolate composition for the preparation of heat resistant chocolate articles, a process for its manufacture and its working into food stuff articles are described. The method comprises dispersing into a mass of couched chocolate, which may optionally be tempered, an emulsion of “water in a fat substance”, of which at least a fraction is in solidified form, such dispersing being carried out at a temperature where said mass, although in fluid form, is in a condition of melt equilibrium with the crystallization germs of the fat substance therein. Furthermore, this document discloses a tropicalized chocolate article or article containing tropicalized chocolate.
GB 1,000,159 discloses a heat resistant chocolate article and a process for its manufacture. Specifically, it describes a heat resistant chocolate article which does not adhere to the wrapper at temperatures exceeding 30° C. The document discloses the preparation of a finely ground amorphous sugar mixture from sucrose and an anti-crystallizing substance such as glucose syrup or invert sugar. This amorphous sugar mixture (at 1-10%) is then mixed with a couched conventional chocolate mass (or “compound mass”) that contains crystalline sucrose. The mass is then tempered in the conventional way followed by shaping and cooling. After hermetically wrapping, the product is stored for between 10 and 60 days at 20° C. and 35° C. During this treatment the amorphous sugar particles stick together forming a sponge like network that prevents collapse at more elevated temperatures. This approach could theoretically be applied for compounded or enrobed products but due to the amorphous sugar, viscosities are too high for use in conventional enrobing machines.
In a second step when water is added, in order to show heat resistance, a “sugar skeleton” must be built up which is usually done by a thermal curing of chocolate (e.g. 2 weeks at >30° C.). EP 1 673 977 discloses a process for manufacturing heat-resistant chocolate or chocolate-like confectionery products wherein an accelerated curing by microwaving is employed. During said process (I) a chocolate mass or a chocolate-like confectionery mass which has been mixed with a water-in-oil emulsion or (II) a chocolate mass or chocolate-like confectionery mass having an increased water content is moulded and then subjected to microwave treatment prior to and/or during cooling to induce the formation of a secondary microstructure and provide heat resistance. Basically, the innovative step of using microwave treatment for accelerated curing is also applicable for enrobed products. However, when mixing chocolate with a sorbitol solution the before-mentioned process using a W/O emulsion of the polyol is applied, which has the drawback that it is only applicable for solid tablets/bars.
U.S. Pat. No. 2,904,438 discloses a process for producing heat resistant chocolate, which may be applied for compounded or enrobed products too, wherein a controlled humidity of the contacting atmosphere surrounding the shaped product is maintained. During said process a heat resistant milk chocolate product which comprises ingredients of a milk chocolate product with a protein and a humectant (i.e. an edible hygroscopic compound) is prepared. The improvement consists in maintaining a controlled humidity of the contacting atmosphere during the roll refining operation at below 45% relative humidity, and then, after the forming step, maintaining a controlled humidity of the contacting atmosphere on the shaped product at above 50% relative humidity at a temperature below the melting point of the composition for a period of time sufficient to render the chocolate self-sustaining at temperatures above the melting point of cocoa butter. Furthermore, this document discloses a heat resistant milk chocolate product obtained by this method. Suitable humectants are inter alia mannitol, propylene glycol, glycerine, sorbitol and the like. Preferably, humidifying takes place after the composition has been formed into its final shape, e.g. when wrapped in moisture permeable packing.
A further embodiment of the process described in U.S. Pat. No. 2,904,438 is disclosed in CH 410 607. Therein, the maintenance of the controlled humidity of the contacting atmosphere on the shaped product at above 50% after the forming step is achieved by steadily moving the product through a moisturization chamber. The speed of moving is adjusted in a way that the amount of moisture, which has been taken up by the product before it leaves the chamber, is sufficient to prevent it from melting at temperatures above the melting point of cocoa butter.
However, in practice this kind of producing heat resistant chocolate can hardly be applied to compounded or enrobed chocolate confectionaries, which themselves exhibit water absorbing properties, such as biscuits, wafers and the like, and whose quality is thus adversely affected by the absorption of water. Moreover, in a chocolate coated product delamination of the chocolate coating from the interior may be observed during such processes The interior which usually has low moisture content and therefore being hygroscopic, is absorbing moisture from the high rel. humidity atmosphere thus expanding its volume which is the typical root cause for delamination. It also takes a long time and therefore this method is not suited for mass production. Further drawbacks are sugar bloom once the moisture is condensing on the product and an inhomogeneous distribution of water, which only migrates into the outer shell of the chocolate, thereby creating a hard crust, which is quickly destroyed upon touching, and under which the remaining chocolate is not heat resistant.
In U.S. Pat. No. 4,812,318 the problem of accelerated firming after mixing conventional chocolate and a polyol solution is solved by an extrusion approach. Utilizing concentric nozzles the chocolate is after the addition of the polyol simultaneously co-extruded with a non-aqueous stabilized batter material. The co-extruded entity is then briefly cooked in a microwave oven in order to obtain a wafer batter coated with heat resistant chocolate. Drawbacks of this approach are that during microwave cooking tempering of the chocolate is destroyed and that a certain thickness of the prepared shell is required.
US 2007/0259070 describes a process for coating a confectionery product with a polyol, such as sorbitol, by an atomizing spray application of the molten polyol. Afterwards an infra-red treatment is applied for drying the coating.
US 2006/0198924 describes a similar process of using pure sorbitol at high temperatures close to its melting point for the preparation of a coated confectionery product, wherein the molten sorbitol is sprayed on a confectionery product and wherein a drying air flow may be supplied to the confectionery while the coating layer(s) is/are applied.
However, these approaches deliver a hard sorbitol shell which does not resemble chocolate in its appearance. Moreover, molten sorbitol requires a high temperature which destroys the tempering of the chocolate and liquefies the chocolate which will eventually bloom and which will harm the shape. Thus, these approaches would only work for coating harder confectionery products not comprising chocolate such as candies, fudge or the like.
US 2006/0198924 also describes a pancoating process. Pancoating is in general applicable for small bites as well as fragile centers such as puffed cereals, wafers or biscuits. However, for panning a more or less sperical shape of the centers is required, i.e. it does not work for tablets, bars and the like.
WO 2006/040127 discloses a process for coating a confectionery product (e.g. chocolate) on all sides except one with a thin film, which preferably comprises modified starches, plasticizers, an acidity regulator and emulsifier, dissolved or dispersed in water. Also, film coatings using compounds such as sugars, waxes, shellac or polyols may be suitable, so as to provide the product with an improved heat stability. This film is applied as a protective layer onto the chocolate and does not change the properties of the chocolate itself.
In U.S. Pat. No. 3,556,814 a process is described wherein a chocolate coated candy bar is covered with a protective surface by dipping it into a propylene glycol-gelatin-sorbitol melt at 110° C. However, this approach does not deliver a homogeneous coating layer of heat resistant chocolate but two separated layers and the outer layer does not resemble chocolate like appearance, but would deliver a grayish, white surface. Also, within the inner layer—due to the high temperature during the process—all tempering of chocolate will be destroyed leading to uncontrolled re-crystallization of chocolate and thus to fat bloom and crumbly texture. Due to the high temperature, also the shape will suffer.
In summary, none of the processes described in the prior art allows for the production of a confectionery product comprising heat resistant chocolate or a heat resistant compound mass, wherein the above described problems, in particular the preparation of compounded or enrobed products such as heat resistant chocolate coated wafers, biscuits or the like, are solved.